1. Field of the Invention
The present invention relates to a plasma display panel (also designated as a PDP hereinafter), and particularly to an AC driven PDP of surface discharge type which is driven with AC signals.
2. Description of Related Art
In recent years, the AC driven PDPs of surface discharge type have been expected as a large and thin color display apparatus.
FIG. 6 shows a cross-sectional view of one example of the structure of an AC driven PDP of surface discharge type.
Referring to FIG. 6, two pairs or more of row electrodes X and Y are laid on a glass substrate 21 to be a display screen side, the row electrodes extending in parallel to each other. The row electrodes X and Y are covered with a dielectric layer 24. Each of the row electrodes X and Y is comprised of a transparent electrode 23a formed of a transparent conductive film, and a metal electrode 23b of a metal film formed on the electrode 23a in order to supplement the conductivity of the transparent conductive film with the metal film. The metal electrodes 23b are stacked on the ends portion of the transparent conductive films 23a opposite to a discharge gap G respectively.
The dielectric layer 24 is comprised of a first dielectric layer 24a which uniformly covers up the inner surface of the glass substrate 21 and the row electrodes X and Y, and a second dielectric layer 24b, i.e., a raising dielectric layer which formed on the first dielectric layer 24a at the corresponding portion to the metal electrode 23b. The second dielectric layer 24b causes the surface of the dielectric layer 24 to locally rise at the corresponding portion to the metal electrode 23b. Since the second dielectric layer 24b is formed with approximately the same width as that of the metal electrode 23b and in parallel to the metal film and locally forms a slightly elevated bank on the surface of the dielectric layer 24, the layer 24b restricts spreading of discharge, thereby preventing adjoining discharge cells from erroneously discharging. A protection layer 25 of MgO is formed on this dielectric layer 24.
On the other hand, a plurality of column electrodes 26 are formed on the inner surface of a glass substrate 22 to be a back side in parallel to one another at predetermined intervals therebetween, and a fluorescent layer 27 is formed on the column electrodes 26 and the inner surface of a glass substrate 22.
The glass substrate 21 of the display screen side and the glass substrate 22 of the back side are secured apart from each other in such a manner that the row electrodes X and Y perpendicularly cross the column electrodes 26 in order to define a discharge space 28 between the inner surfaces of the substrates facing each other. The discharge space 28 is filled with a rare gas, and the assembled panel is sealed hermetically.
Ribs or partitions (not shown) having a predetermined height are formed between the column electrodes 26 on the back-side glass substrate 22 respectively to separate the column electrodes 26 and the plural pairs of row electrodes X and Y, thereby defining a unit of light-emitting regions having light-emitting surfaces with a predetermined area.
The dielectric layer 24 is formed by coating a low-melting point glass paste containing, for example, lead oxide (PbO) on the row electrodes X and Y and annealing it. Since the metal film needs to have a low electric resistance in order to supplement the conductivity of the transparent conductive film, Al (aluminum), Al alloy, Ag (silver), Ag alloy or the like is used for the metal film.